This invention relates to rotary compressors and particularly to an improved discharge check valve and retainer means assembly with positioning means securing the assembly in a valve chamber in a manner that creates a continuous radius backing surface for the valve.
In conventional rotary compressors, particularly of the type used in refrigeration systems, the compressor comprises a cylindrical wall member and end plates defining a compression chamber or cylinder, a rotor eccentrically mounted within the cylinder and a vane slidably mounted within the cylindrical wall for engagement with the periphery of the rotor to divide the chamber into a high pressure side and a lower pressure side. In operation of such a compressor, rotation of the rotor draws the gas into the low pressure side and discharges the compressed gas through a discharge port communicating with the high pressure side of the chamber on the opposite side of the vane from the lower pressure port. The high pressure gas passing through the discharge port enters a valve discharge chamber. Located in this valve discharge chamber is a check valve customarily of the reed type that is biased against the outlet opening to prevent back flow, but yieldable under gas pressure to permit the compressed gas to flow into the valve discharge chamber. Customarily, the valve is provided with a backing retainer that limits the movement of the valve in its open position. The radius of the valve retainer, against which the valve rests during the discharge period, is critical and any distortion or flatness of the retainer can cause discharge valve damage or breakage. Flatness, for example, can also cause the relatively thin reed valve to stick or remain in its open position and, accordingly, cause back flow of refrigerant gas. Valve sticking also causes the valve to more heavily strike against the seat causing valve breakage.
In some prior art discharge valves, such as those in 3,003,684-Tarleton, provide retainers that are ridged and formed to allow restricted movement of the valve. When this type construction is used, it requires great care in the forming operation to insure that a constant radius is formed free from distortion and flatness. In other prior art pertaining to discharge valve assemblies, such as those disclosed in U.S. Pat. Nos. 4,088,424-Bannister et al, and 4,137,726-Watada, valve and retainer assemblies are disclosed wherein the retainer is dimensioned to yieldably engage portions of a valve chamber to securely hold the assembly relative to the discharge port.
The present invention is directed to an improved check valve and retainer assembly wherein the retainer is dimensioned to yieldably engage portions of the valve chamber in a manner that creates a backing for the valve, and presents a continuous radius to the valve in its open position.